Filter assembly

ABSTRACT

A fuel filter assembly includes a header and a can-shaped housing removeably attached to the header. The can-shaped housing has an upper rim portion provided with a plurality of notches therein. A filter unit has an upper end cap provided with a plurality of tabs extending from the periphery and positioned within the notches of the housing. The spacing of the notches about the axis of the housing must be the same as the spacing of the tabs about the axis of the filter unit to permit the filter unit and housing to be properly assembled, thereby preventing the use of an incorrect filter unit within the housing. Additionally, the header has a plurality of key slots that receive the tabs on the filter unit. The spacing of the key slots and tabs must be the same to permit the housing and received filter unit to be properly connected to the header.

TECHNICAL FIELD

This application relates generally to filter assemblies employed inconnection with internal combustion engines. More particularly, thepresent application relates to filter assemblies having a replacementcartridge for removing foreign particles and/or separating water fromfuel of the fuel supply system of an internal combustion engine.

BACKGROUND

It has long been recognized that trouble-free operation of an internalcombustion engine requires some form of filtering of the fuel consumedby the engine. In particular, the absence of high standards of qualitycontrol in diesel fuel supplies dictates that an effective fuel filterbe incorporated into the fuel supply system for a diesel engine. It isnot uncommon for diesel fuel to contain significant quantities ofabrasive particles and water. The abrasive particles present thepotential for permanent damage to components of the fuel injectionsystem. The abrasive particles can adversely affect the performance ofthe fuel injection pump by destroying the ability of the fuel injectionpump to precisely meter and deliver fuel at high pressures. The presenceof water in the diesel fuel supply can cause rusting of enginecomponents, and during freezing conditions, can result in interruptionof the fuel injection system and/or seizure of moving components.

A number of conventional fuel filter systems perform the dual functionsof removing particulate matter from the diesel fuel and separating waterfrom the fuel. Conventionally, the fuel filter systems employ adisposable filter cartridge which is replaced at pre-establishedintervals of filter usage. In practice, the filter cartridgerequirements may vary depending upon such characteristics as the typeand make of the internal combustion engine, the specific applicationsfor which the engine is employed, the climate in which the combustionengine is operated and/or regional characteristics as to the quality ofthe fuel supply. The filter cartridges thus commonly vary as to theirdimensions, their capacity, and the qualities of their filter media.

One of the problems that is frequently encountered in connection withreplacement of the filter cartridge is ensuring that the replacedcartridge is compatible with the filtering requirements for the fuelsystem. Because numerous types and qualities of filter cartridges maydimensionally conform to the base of a given filter system, thereplacement filter cartridge frequently does not comply with thespecifications for the filter system, thereby jeopardizing the integrityof the fuel filtering system. Use of an incompatible filter cartridgecan have very serious effects on the operation of the internalcombustion engine, and may also be unnecessarily expensive when a lesscostly cartridge is fully suitable. Frequently, either the owner or themaintenance personnel servicing the internal combustion engine aretotally unaware of the replacement filter cartridge specifications andrequirements and unknowingly jeopardize the integrity of the filteringsystem by using non-conforming filter cartridges. There are alsoinstances where inferior or improper replacement filter cartridges areintentionally installed without the knowledge of the owner or operatorof the vehicle.

U.S. Pat. No. 5,035,797, which is assigned to the assignee of thepresent invention, discloses a key system for a filter system intendedto address issues of filter cartridge compatibility. Fuel filter systemscommonly comprise fuel inlet and outlets disposed in a base or headerand a disposable filter cartridge that mounts to the base. Disposablefilter cartridges constructed according to this invention have slotswhich are designed to mate with axial projections of the base. Theprojections interfere with the use of an incompatible cartridge byinterfering with the mounting and sealing of the cartridge to the base.

Fuel filters have typically been constructed in the form of a metal can,permanently enclosing the filter element in a single use assembly. Whilethese assemblies have proved to be effective and reliable, they are lessthan ideal in terms of waste of materials and disposal cost.

Increased awareness of environmental protection and recycling ofmaterials have led to a need for more efficient filtration systemshaving a minimum disposable component. In addition, environmentalprotection agencies seeking to reduce the volume of waste itemsassociated with the automotive and trucking industries may no longerpermit unrestricted disposal of used fuel filters into the normal wastestream, thereby necessitating specialized and consequently moreexpensive disposal.

SUMMARY OF THE INVENTION

According to one aspect of the disclosure there is provided a fuelfilter assembly including a header and a housing removeably attached tothe header. The housing has an upper edge portion having a plurality ofnotches therein. A filter unit is positioned within the housing, forminga cartridge assembly. The filter unit has an upper end cap provided witha plurality of tabs extending from the periphery thereof, the tabs beingpositioned in the notches in the housing.

According to a further aspect, the header may include a downwardlyextending skirt having an inner surface and a plurality ofcircumferentially spaced key slots in the inner surface. The key slotsare equal in number to and have the same circumferential spacing as thetabs and are adapted to receive the tabs when the housing and receivedfilter unit are inserted into the header.

According to another aspect of the disclosure, there is provided afilter unit for a fuel filter assembly that includes a unit elementhaving a generally cylindrical profile. The filter element includesupper and lower end caps at the ends of the filter element. The upperend cap has a plurality of tabs that extend from the outer peripherythereof. The distal end of each of the tabs has a down-turned fingerportion spaced from the filter element to form a gap between the insidesurface of the down-turned finger portion and the filter element.

According to a yet another aspect of the disclosure, there is provided afilter unit and housing assembly for connection to a header of a fuelfilter assembly that includes a housing having an upper edge portion,the upper edge portion having a plurality of notches therein spacedabout the housing, the filter unit includes a plurality of tabsextending from the outer periphery of the upper end cap. The tabs areequal in number to the notches in the housing and are spaced about theaxis of the filter unit in the same configuration as the spacing of thenotches about the axis of the housing, with the tabs being positioned inthe notches.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a vertical sectional view of a filter assembly according tothe present disclosure;

FIG. 2 is a perspective view of the bottom portion or bowl of thehousing of the filter assembly of FIG. 1;

FIG. 3 is a perspective view of the top portion or cap of the housing ofthe filter assembly in claim 1;

FIG. 4 is a perspective view of the housing with the cap of FIG. 4attached to the bowl of FIG. 3;

FIG. 5 is a vertical sectional view of the combined cap and bowl of FIG.4;

FIG. 6 is an enlarged partial vertical sectional view in perspective ofa portion of the filter assembly of FIG. 1 showing the details of theinterconnection of the header, housing and filter unit;

FIG. 7 is a perspective view of the filter unit used in the filterassembly of FIG. 1;

FIG. 8 is a top perspective view of the header of the filter assembly ofFIG. 1;

FIG. 9 is a perspective view of the bottom inside of the header shown inFIG. 7; and

FIG. 10 is a perspective view of the locking collar of the fuel filterassembly of FIG. 1.

DETAILED DESCRIPTION

Referring to the drawings and particularly FIG. 1, the fuel filterassembly 2 comprises generally a header 4 to which is removeablyattached a can-shaped housing 6. A filter unit 8 is positioned withinthe can-shaped housing 6 as shown. A locking collar 10 serves to attachthe can-shaped housing 6 containing the filter unit 8 to the header 4.

The can-shaped housing 6 may be formed from two separate components asshown in FIGS. 2 and 3, each fabricated from a suitable material such assteel. The two pieces include a bottom bowl-shaped member 12 and top cap14. The bowl-shaped member 12 has a circular flange 16 adjacent itsupper end that extends perpendicular to the axis of the bowl as shown inFIG. 2. The top cap 14 as shown in FIG. 3 has a circular flange 18 thatextends perpendicular to the axis of the top portion. The two flanges 16and 18 provide means whereby the bowl-shaped 12 and top portion 14 arejoined together by a conventional rolled seam 20. The resulting seam 20provides a circumferentially extending shoulder 22 about the housing 6as shown in FIGS. 8 and 9.

The bowl-shaped member 12 is hollow, has a cylindrical wall portion 24and is closed at its lower end 25. An aperture 26 is provided in itslower end 25 as shown on FIGS. 1 and 5 that is adapted to receive adrain cock (not shown). The drain cock is typically used for drainingwater separated from the fuel, and can also serve the ecologicalfunction of draining fuel from the housing 6 before the housing isseparated from the header 8.

As shown particularly in FIGS. 5 and 6, the top cap 14 has a cylindricalwall that includes a circular rim portion 28, an upper cylindrical wallportion 30 having an outer diameter greater than the rim portion 28 anda lower cylindrical wall portion 32 having an outer diameter equal tothe outer diameter of the upper cylindrical wall portion 30. An inwardlyextending circumferential groove 34 is formed between the uppercylindrical wall portion 30 and the lower cylindrical wall portion 32. Asealing ring, such as an O-ring 36, is mounted in the groove 34.

A plurality of notches 38 is provided in the upper edge of rim portion28 of the top cap 14 of the housing 6. The notches 38 extend downwardlyfrom the top surface of the rim portion 28 to a point slightly spacedupwardly from the upper cylindrical wall portion 30 as shown in thedrawings. There are three such notches 38 shown although an alternativeplurality of such notches may be provided. The three notches 38 shownare symmetrically spaced about the axis of the housing. The spacingbetween each of the notches may be varied to provide differentconfigurations that are unique to a given fuel filter assembly.

Although the housing 6 has been shown as being formed from two members,it may be fabricated as a one-piece element. For example, the housing 6may be a one-piece injection-molded member using a suitable plasticmaterial. The plastic material may be transparent to permit inspectionof the water level in the housing. Alternatively, the housing 6 may becast from aluminum.

The filter unit 8 includes a filter element 40 having an outercylindrical profile. The filter element 40 may be a fan folded paperelement in the form of a cylinder with a center aperture 42 thattypically filters particulates and separates water from fuel. An upperend cap 44 is provided at the top of the filter element 40 and a lowerend cap 46 is provided at the bottom of the filter element 40. The endcaps 44 and 46 enclose the axially spaced ends of the filter element 40and provide structure to the paper element. The upper end cap 44 has anaperture 48 that is coaxial with the axis of the aperture 42 through thefilter element 40. A grommet 50 is mounted in the aperture 48 of theupper end cap 44. The grommet 50 has a circumferential slot 52 thatreceives the edge portion 54 defining the aperture 48 in the upper endcap 44 to secure the grommet 50 on the filter unit 8. The grommet 50 hasan axial bore 55 therethrough that is coaxial with the axis of thefilter element 40.

The upper end cap 44 of the filter unit 8 includes a plurality of tabs56 as shown in FIGS. 6 and 7 that extend outwardly from the outerperiphery thereof. A down-turned finger portion 58 is provided at theends of each of the tabs 56 that forms a space or gap 60 between theouter periphery of the filter element 40 and the inner surface 61 of thefinger portion 58. The gap 60 should be of a width such that thethickness of the rim portion 28 of the housing 6 can be inserted withinthe gap 60 and still leave a space between the inner surface 62 of therim portion 28 and the outer periphery of the filter element 40 as shownin FIG. 6.

The number of tabs 56 is equal in number to the notches 38 in thehousing 6. The tabs 56 are spaced about the axis of the filter unit 8 ina manner identical to the spacing of the notches 38 about the axis ofthe housing 6. The width of each of the tabs 56 and notches 38 should besuch that each tab 56 can be positioned within a corresponding notch 38with little or no rotational movement occurring between the filter unit8 and the housing 6. The outer diameter of the upper end cap 44(excluding the tabs) is less than the inner diameter of the rim portion28 of the housing 6 so that there is a gap 63 between outer periphery ofthe upper end cap 44 and the inner surfaces of the rim portion 28 andgroove 34 when the filter unit 8 is inserted into the housing 6 as shownin FIG. 1.

With the arrangement of tabs 56 and notches 38 as described above, thefilter unit 8 can be inserted into the top of the housing 6, moveddownwardly into the housing 6 and rotated until the tabs 56 are alignedwith the notches 38 at the top of the housing 6. Further insertion ofthe filter unit 8 into the housing 6 will result in the tabs 56 beingpositioned within the notches 38 and the down turned finger portions 58being positioned on the outside of the rim portion 28 of the cylindricalwall of the housing 6. The finger portions 58 engage the outside wall ofthe rim portion 28 and serve to maintain the filter unit 8 in a centeredposition coaxial within the housing 6.

As mentioned above, three notches 38 are provided in connection with thehousing 6 that are spaced symmetrically about the axis of the housing 6.With a housing 6 having this configuration, only a filter unit 8 havingthree tabs 56 with a similar spacing about the axis of the filter unitcan be properly inserted into the housing 6. Incompatible housings 6 andfilter units 8 cannot be properly assembled.

The number of, or special orientation of the notches about the axis, canbe changed so that only a unit 8 having that configuration of tabs 56will be accepted within the housing 6. A compatibility matrix isprovided comprising an infinite number of configurations of compatiblehousings 6 and filter units 8 to differentiate between filter assemblieshaving different flow capabilities, filter media, disposal options,ecological qualities or other characteristics.

With reference to FIGS. 8 and 9, the header 4 includes a downwardextending skirt 64 into which the cap 14 of the housing 6 is inserted.As shown in FIGS. 1 and 4-6, the inside diameter of the cylindrical wall24 of the bowl 12 of the housing 6 is larger than the outside diameterof the cylindrical wall portions 30 and 32 of the cap 14, so that uponformation of the rolled seam 20, a U-shaped pocket 66 is formed thatextends around the housing 6 with the shoulder 22 formed by the rolledseam 20 on the outside of the housing 6. The filter unit 8 and housing 6assembly is inserted into the header 4 so that the upper portion of thehousing 6 and upper end cap 44 of the filter unit are positioned withinthe skirt 64 and the sealing ring 36 is in sealing engagement with theinside surface of the skirt 64. The bottom end 68 of the skirt 64extends into the pocket 66 as shown in FIG. 6.

The inside surface of the skirt 64 of the header 4 is provided with aninwardly protruding shoulder 70 extending around the upper portion ofthe inside surface of the skirt 64 and projecting downward from theinside upper surface 74 of the header 4. The shoulder 70 includes aplurality of circumferentially spaced key slots 76 in its bottom surface78 that are adapted to receive the tabs 56 on the filter unit 8 when theassembly of the housing 6 and filter unit 8 is inserted into the header4. The number and circumferential spacing of the key slots 76 mustcoincide with the number and spacing of the tabs 56 on the filter unit 8to enable the assembly of the housing 6 and filter unit 8 to be properlyinserted into the header 4 and secured by the locking collar 10. If thetabs 56 are of different configuration than the keys slots 76, thehousing 6 and filter unit 8 assembly will not be properly received inthe header 4 to allow the locking collar 10 to be properly secured.Also, if the tabs 56 on the top end cap 44 of the filter unit 8 are notproperly located in the notches 38 of the housing 6, the assembly of thefilter unit 8 and housing 6 cannot be properly inserted into the header4 to be locked by the locking collar 10.

The skirt 64 of the header 4 is provided with a plurality of lockinglugs 80 on its outer surface that are engaged by the locking collar 10to secure the housing 6 to the header 4. The locking collar 10 surroundsthe housing 6 and includes an inwardly extending flange 82 as shown inFIG. 6 that engages the circumferential shoulder 22 around the housing6.

As shown in FIG. 10, the locking collar 10 is provided with a series ofcircumferentially spaced cutouts 84 that extend downward from its topsurface and communicate with a circumferentially extending ramp 86. Theramp 86 tapers downward from its connection with the cutout 84 to anon-tapering slot 88 defined by surfaces that lie in a planeperpendicular to the axis of the locking collar 10. A detent portion 90interconnects the tapering ramp 86 and non-tapering slot 88. The numberof cutouts 84 is equal in number to the number of lugs 80 on the skirt64.

To attach the housing 8 and filter unit assembly to the header 4, thehousing 6, with the filter unit 8 in place, is inserted into the header4. The tabs 56 on the filter unit 8 extend up into the key slots 76 inthe shoulder 70 that extends downward from the inside bottom surface 74of the header 4.

The locking ring 10 is positioned around the housing 6 and is moved upso that lugs 80 of the header 4 enter the cutouts 84 in the locking ring10. As the locking ring 10 is rotated, the tapered ramp 86 rides alongthe lugs 80 of the locking ring 10 whereby the locking ring 10 movesupwardly relative to the header 4 pulling the housing 6 upward with itby virtue of the engagement of the flange 82 with the shoulder 22 on thehousing 6. The locking ring 10 is rotated until the detent portion 90 bypasses the lugs 80 and the lugs 10 are positioned in the non-taperingslot 88.

In an alternative header/collar configuration, the header includesradially protruding threads which are engaged by complementary threadson the collar (not illustrated). The collar is rotated so that thethreads bring the collar toward the header. The threads include detentsto define the fully installed position of the collar with respect to theheader. The engagement between the collar 10 and header 4 illustrated inFIGS. 1, 6 and 8-10 should be considered interchangeable with a threadedengagement.

The header 4 is provided with an inlet port 92 and an outlet port 94 asshown particularly in FIG. 1. The header 4 also includes a centraldownward extending circular post 96 that is adapted to extend throughthe grommet 50 in the filter unit 8 when the filter unit 8 and housing 6assembly is connected to header 4. The inlet port 92 is connected by aninlet passage 97 to the area within the header 4 immediately above thefilter unit 8. The output port 92 is connected to the center aperture 42of the filter unit 8 by means of an outlet passageway 98 extending fromthe outlet port 94 radially through the header 8 and downwardly throughthe central downward extending post 96 and opening into center aperture42 of the filter unit 8.

With this arrangement, the flow path of the fuel is through the inletport 92 and inlet passageway 97 into the area above the top of thefilter unit 8. The fuel passes through the gap 63 between the outerperiphery of the upper end cap 44 and the inner surface of thecylindrical rim portion 28 of the housing 6 into the interior of thehousing 6 down around the side of the filter unit 8. Fuel then passesthrough the filter element 40 into the central aperture 42 and up thecentral aperture 42 and through the outlet passageway 98 to the outletport 94.

To provide for this flowpath, the outer diameter of the periphery of thetop end cap 44 (excluding the tabs 56) is less than the inner diameterof the cylindrical rim portion 28 of the housing 8. This results in thegap 63 through which the liquid fuel can flow down past the filter unit8 into the interior of the housing 6.

In use, the header 4 is physically attached to a vehicle engine orchassis by means of bolts (not shown) passing through the apertures 100shown in FIGS. 8 and 9. The header 4 provides an inlet and outlet forthe fuel line (not shown). A suitable filter unit 8 of the type designedto be used with that particular vehicle and with the particularconfiguration of notches 38 in the housing 6 is inserted into thehousing 6 with the tabs 56 positioned in the notches 38 and the fingerportions 58 positioned on the outside of the cylindrical rim 28 of thehousing 6. The housing 6 is then inserted into the header 4 so that thetabs 38 are received in the key slots 76 in the inside of the header 4.The locking ring 10 is positioned about the housing and moved upwardlyso that the flange 82 engages the shoulder 22 on the housing and alignedso that its cutouts 84 align with the lugs 80 on the outside of theheader 4. The locking ring is moved toward the header until the lugs 80are aligned with the ramp 86 whereupon the locking ring is rotated untilthe lugs 80 pass the detent portion 90 and enter the non-tapering slot88.

By providing at least three spaced tabs 56 with down turned fingerportions 58, the upper end cap 44 will stay centered and coaxial withthe housing 6 by virtue of the fact that the down turned finger portions56, being in engagement with the outer surface of the cylindrical rimportion 28 of the housing 6, prevents radial movement between thehousing 6 and filter unit 8. This ensures that the flow passage betweenthe outer periphery of the top end cap 44 and the inner surface of thehousing 8 remains symmetrical about the axis of the housing 6.

The key slots 76 in the header 4 control upward movement of the housing6 and filter unit 8 into the header 4. If the tabs 56 on the filter unit8 do not properly align with the key slots 76, and if the tabs 56 arenot properly received in the notches 38 in the top of the housing 6, thefilter unit 8 and housing 6 assembly will not be received into theheader 4 the proper distance. Unless the filter unit 8 and housing 8assembly is properly inserted into the header 4, the locking ring 10cannot be rotated properly.

For example, if the tabs 56 on the filter unit 8 and the notches 38 inthe housing 6 do not match so that the tabs are positioned within thenotches 38, the tabs 56 will rest on the very top edge of the housing 8.Assuming that the notches 38 in the housing 6 and the key slots 76 inthe header 4 are of the same spacial alignment, then, in such a case,when the housing 6 and filter unit 8 assembly is inserted into theheader 4, the nonsymmetrical tabs 56 will engage the shoulder 70 ratherthan enter the key slot 76 and further insertion into the header 4 isprevented. Under this circumstance, the shoulder 22 on the outside ofthe housing 6 is be positioned at a point axially spaced downward fromthe lugs 80 on the outside of the header 4 such that when the lockingring 10 is moved upwardly, the inclined slot 86 in the locking ringwould not be properly aligned with lugs 80 on the header 4 so that thelocking ring 10 can be properly rotated into the locked position. Thisprevents a housing 6 with a non-matching filter unit 8 from beingconnected to the header 4.

Also, even if the tabs 56 on the upper end cap 44 of the filter unit 8are properly positioned within the notches 38 of the housing 6, if theconfiguration of the notches 56 doesn't match the configuration of thekey slots 76 in the header 4, the housing 6 and filter unit 8 assemblywill not be properly received into the header to enable the locking ringto be properly secured. In this case, the top surface of the tabs 56will engage the shoulder 70 in the header 4 and further insertion of thefilter unit 8 and housing 6 assembly will be prevented. As a result,housing 6 will not be in proper axial position relative to the lugs 80so that when the locking collar 10 is moved upward into a position whereit engages the shoulder 22 on the housing 8, the locking collar 10 canproperly engage the lugs 80 to properly lock the filter unit 8 andhousing 6 assembly in place. Thus even though the filter unit 8 andhousing 6 might match, unless the notches 38 on the housing also matchthe orientation of the key slots 76 in the header 4, the filter unit 8and housing 6 cannot be properly attached to the header 6.

By virtue of the above-described construction, a filter cartridgeassembly is provided in which an ecological filter unit may be utilizedand which provides for an infinite number of configurations todifferentiate between filter cartridge assemblies having different flowcapabilities, filter unit disposal options and or other characteristics.

Only when a correctly configured filter unit has been fully received andretained with the housing can the filter unit and housing (cartridgeassembly) properly engage with the header to permit the cartridgeassembly to be properly secured to the header. This will ensure that thecartridge assembly will be one that is compliant with the specificationsof the fuel system of that particular vehicle.

While preferred embodiments have been shown and described, varioussubstitutions and modifications may be made thereto. Accordingly, it isunderstood that the present embodiments have been described by way ofillustration and not limitation.

1. A fuel filter assembly comprising: a header; a housing removeablyattached to said header, said housing including an upper edge portionhaving a plurality of notches therein; and a cartridge unit within saidhousing, said cartridge unit having an upper end cap provided with aplurality of tabs extending from the periphery thereof, said tabs beingpositioned in said notches in said housing.
 2. The fuel filter assemblyof claim 1 wherein said tabs include a finger portion at the endsthereof positioned against the outer surface of the housing.
 3. The fuelfilter assembly of claim 2 wherein there are at least three tabs. 4 Thefuel filter assembly of claim 3 wherein said housing has an axis, saidnotches have a predetermined angular spacing about said housing axis,and said tabs have an angular spacing coincident with said angularspacing of said notches.
 5. The fuel filter assembly of claim 1 whereinsaid header includes radially protruding features and said housingincludes a circumferential rim on its outer surface, and said filterassembly further including a locking ring for engaging said features andsaid rim for locking said housing to said header.
 6. The fuel filterassembly of claim 5 wherein said housing comprises two parts, the firstpart being an upper cap portion having said notches therein and saidsecond part being a bowl-shaped lower portion, said first and secondparts being connected by a rolled seam, said rolled seam providing saidcircumferential rim on said housing.
 7. The fuel filter assembly ofclaim 2 wherein said header includes a downwardly extending skirt havingan inner surface and a plurality of circumferentially spaced key slotsin the inner surface, said key slots being equal in number to said tabsand having the same circumferential spacing as said tabs and beingadapted to receive said tabs when said housing is attached to saidheader.
 8. The fuel filter assembly of claim 7 wherein said header has arim extending around the upper portion of the inside surface of saidskirt, said key slots being formed in said rim.
 9. The fuel filterassembly of claim 7 wherein said skirt has an outer surface, said outersurface having a plurality of lugs thereon, and further including alocking ring for attaching said housing to said header, said lockingring having a portion in engagement with said housing and an uppersurface with a plurality of slots extending downwardly therefrom in theinternal surface that communicate with a slanted internal ramp thereof,each said slot aligned to receive one of said lugs therein to permitsaid locking ring to be moved upwardly and rotated with the keying lugsriding along the slanted ramp.
 10. The fuel filter assembly of claim 9wherein said header has a fuel inlet and a fuel outlet, said fuel inletcommunicating with the interior of said header at a point abovecartridge unit, said upper end cap having a periphery excluding saidtabs that is spaced from said upper edge portion of said housing to forma gap for fuel to flow into the interior of said housing.
 11. The fuelfilter assembly of claim 10 wherein said filter unit has a centeraperture and said header has a center post extending into said aperture,said fuel outlet connected to the center aperture by a passagewayextending though said center post.
 12. The fuel filter assembly of claim1 wherein said housing is molded from plastic or metal.
 13. A filterunit for a fuel filter assembly comprising: a filter element having agenerally cylindrical profile; upper and lower end caps at the ends ofsaid filter element, said upper end cap having a plurality of tabsextending from the peripheral edge thereof, the distal end of each ofsaid tabs having a down-turned finger portion spaced from the filterelement to form gap between an inside surface of said down-turned fingerportion and the filter element.
 14. The filter unit of claim 13 whereinthere are at least three tabs.
 15. The filter unit of claim 13 whereinthe tabs have a predetermined spacing about the axis of the filterelement.
 16. The filter unit of claim 13 wherein said filter element hasa center aperture and said upper end cap has an aperture coaxial withthe center aperture, and further including a grommet mounted in theaperture in said upper end cap.
 17. A filter cartridge assembly forconnection to a header of a fuel filter assembly comprising: a housinghaving an upper edge portion, said upper edge portion having a pluralityof notches therein spaced about an axis of the housing, a filter unitincluding a filter element having a generally cylindrical outer profileand an upper and lower end cap, said upper end cap having a plurality oftabs extending from an outer periphery thereof, said tabs being equal innumber to said notches in said housing and being spaced about the axisof said filter unit in the same configuration as the spacing of saidnotches about the axis of said housing, said tabs being positioned insaid notches.
 18. The filter cartridge assembly of claim 17 wherein eachof said tabs has a down-turned portion at its end, said down-turnedportion positioned against an outside surface of the housing.
 19. Thefilter cartridge assembly of claim 18 wherein there are at least threenotches.
 20. The filter cartridge assembly of claim 18 wherein theperiphery of said upper end cap excluding said tabs is radially spacedfrom said upper edge portion of said housing to form a gap between theupper end cap and the housing.